Abstract: In large-scaled WS2 monolayer film, which was grown by chemical vapor deposition on SiO2(300 nm)/Si substrates, huge amount of monolayer WS2 bubbles with a shape of spherical cap and widely distributed sizes have been successfully created by high-temperature treatment under protection of Ar gas flow. In optical and fluorescence images of the monolayer WS2 bubbles with large sizes, obvious interference rings have been observed on the bubble’s surfaces. In line scans and mapping images of photoluminescence (PL) and Raman, oscillatory behaviors have been observed not only for the PL and Raman peak intensities but also the peak positions. Considering the laser beam size (1 mm) used in the PL and Raman measurements, the observed oscillations of peak intensity and position have been attributed to the enhanced and lowered local heating effects owing to the interference strengthened and weakened laser light strength on the bubble surface. This heating effect has been verified via a designed experimental measurement.

Biosketch： Zhongyuan Liu is now a professor at the State Key Lab of Metastable Materials Science & Technology, Yanshan University, Qinhuangdao. Liu obtained a PhD degree at 2003 from the Department of Physics and Astronomy, University of Nebraska-Lincoln. He has obtained the National Fund for Outstanding Youth at 2010. His research studies involve magnetic thin films and two-dimensional materials. So far, he has published more than 170 papers, including Adv. Mater.、Adv. Funct. Mater.、PNAS、PRL.

According to the latest Nature Publishing Index (NPI) Asia-Pacific and The Nature Publishing Index China, University of Science and Technology of China tops in Chinese universities again. The rankings are based on the number of papers that were published in Nature journals during the last 12 months.